Archived posting to the Leica Users Group, 2008/03/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Peter, I like your idea of experimentingon this - just one remark ; from 1.4 to 2 you do get "about 1/3 more light" (well a little over, but not much more) or am I mistaken? Remember also that the precise focal length may vary - a well known fact for Leica users, I know - but it may also affect other brands, and consequently the ratio Focal length / aperturediameter also varies. Some brands (Pentax for instance) had a 1.8 55 and a 1.4 50 , where's the trick? What amount of light actually gets through? I never noticed anything about closing down, so I'll be trying too with other gear, but the phenomenon should be make independent I guess, thanks for the insight phx Peter Klein wrote: > Richard: Would you do me a favor? Meter something once at a medium > aperture. Then take a series of equivalent manual exposures. Such as: > > 1/30, f/4 > 1/60, f/2.8 > 1/125,f/2 > 1/250,f/1.4 > > Are resulting images the same exposure, or is f/1.4 much darker? If > you're game, try the whole range of f-stops. Do things get out of > whack again at f/11 or f/16? > > I noticed that with my E-1 and a Zuiko 50/1.4, I got only about 1/3 > stop more light going from f/2 to f/1.4. So the 50/1.4 was really > only a 50/1.8 for practical purposes. This might have something to do > with the angle the light hits the sensor wells, and something gets cut > off faster than about f/2. > > There were actually two factors. Not only did the sensor respond > differently at extreme apertures, but metering was also off at both > large and small stops. So the effects of the two factors combined, > making things very confusing until I separted them. > > The result was the the OM lenses couldn't be relied upon without > knowing a compensation factor for wide open and closed down. All this > behavior has been reported by others (with the usual Internet > flamefests over the cause, and whether the reporter knows how to use > his camera). > > I wonder if the E-3 is the same, or if it's more forgiving with OM > lenses. > > That said, if you have a OM Zuiko macro lens, try it with the E-3 and > you might just marvel at the image quality. My 50/3.5 OM Macro gave > me image quality on the E-1 like no other lens I tried. And the > 100/2.8 makes a nifty 200mm-equivalent telephoto. > > --Peter > >> Who says it can't be done? >> http://www.dragonsgate.net/pub/richard/PICS/_3031364.jpg >> http://www.dragonsgate.net/pub/richard/PICS/_3031365.jpg >> http://www.dragonsgate.net/pub/richard/PICS/_3031366.jpg >> >> The trusty 50/1.4 Zuiko at 1.4. The E-3 VF is definitely as good if >> not better than the OM-4 when it comes to manual focusing. > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >